xonfig: added links (xonsh#5500)

Added links to xontribs in `xonfig web`

### After

<img width="764" alt="image"
src="https://github.com/xonsh/xonsh/assets/1708680/cf5a32e6-f04c-4718-a175-2bfc863632ba">


## For community
⬇️ **Please click the 👍 reaction instead of leaving a `+1` or 👍
comment**

---------

Co-authored-by: a <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

xonsh/webconfig/routes.py

@@ -256,6 +256,34 @@ def xontrib_card(self, name, data):
  ]
 
  def get(self):
+ yield t.card()[
+ t.card_body()[
+ t.card_title()["Popular xontrib sources"],
+ t.card_body()[
+ t.li()[
+ t.a(href="https://github.com/topics/xontrib")[
+ "Xontribs on Github"
+ ]
+ ],
+ t.li()[
+ t.a(href="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/xonsh/awesome-xontribs")[
+ "Awesome xontribs"
+ ]
+ ],
+ t.li()[
+ t.a(
+ href="https://xon.sh/api/_autosummary/xontribs/xontrib.html"
+ )["Core xontribs"]
+ ],
+ t.li()[
+ t.a(href="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/xonsh/xontrib-template")[
+ "Create a xontrib step by step from template"
+ ]
+ ],
+ ],
+ ]
+ ]
+ yield t.br()
  for name, data in self.xontribs.items():
  yield t.row()[t.col()[self.xontrib_card(name, data),]]
  yield t.br()